Differential mechanism for accounting-machines.



H. A. MARTIN.

DIFFERENTIAL MECHANISM FOR ACCOUNTING MACHINES. APPLICATION FILED020.31. 1913.

1,153,328. PatentedSept. 14, 1915.

3 SHEETS-SHEET I.

. F/AV.

H. A. MARTIN.

DIFFERENTIAL MECHANISM FOR ACCOUNTING MACHINES.

. APPLICATION FILED DEC.3I, 1913. 1,153,328. PatentedSept. 14, 1915.

3 SHEETSSHEET 2.

'HZ-ZZ Show a; s

,CDLUMBIA PLANOURAPH (IO-.WASHINIJTON, n. c.

H. A. MARTlN.

DIFFERENTIAL MECHANISM FOR ACCOUNTING MACHINES.

APPLICATION FILED DEC.3I, I913- PatentedSept. 14, 1915.

3 SHEETS-SHEET 3.

awuawtoz Meme/r32 U cocperate only with the keys of its appro- UNITEDSTATES PATENT OFFICE.

I-IAAKON A. MARTIN, OF DAYTON, OI-IIO, ASSIGNOR TO THE NATIONAL CASHREGISTER COMPANY, OEDAYTO'N, OHIO, A CORPORATION OI? OHIO, (INCORPORATEDIN 1906.)

To all whomit mag concern Be it known that I, HAAKON Mnnrrn, a

citizen of the United States, residing at. Dayton, in the county of-Montgomery and State of Ohio, havefinvented certain new and usefulImprovements in Differential Mechanism for Accounting-Machines, of whichI declare the following to be a full, clear, and exact description. I I

I This invention relates'to accounting'machines and more particularly tothe arrange ment of two groups of keys in one bank, each group beingarranged to perform different functions. I c

It was the principal object of thls invention to provide an improvedarrangement of 1 two differential mechanisms, so that each differentialmechanism will be controlled by a corresponding group of two groupsofkcys c In the preferred form ofembodiment disclosedherein,

which comprise a single bank.

both of the diflerential mechanisms controlled by the two groups of keysin the one bank are driven from the same shaftand each carries latchingmechanism adapted to priate group. p v 1 The particular form of machineto which the present improvements have been applied is that shown anddescribed in Letters Patent of the United States issued April 13,

1 897, to J. P. Cleal and F. A. Reinhart and numbered 580,378. In theillustrative form shown herein, a group of amount keys is arrangedin aslnglebank .Wltll speclal keys controlling a special indicator whichmaybe used to indicate either the particular clerks operating themachine, or the different classes of transactions involved in the busi-The bank of keys is arranged in a above mentioned patent, anddifferential mechanism, controlled by the special keys,

is arranged on one side ofan upright'framef supporting the key frame,while the differential mechanism, controlled by the amount keys is ontheother side of this upright frame. s

Although in the preferred form shown herein, special keys control aspecial indicatorand the amount keys control amount differentialmechanism,it will be apparent that the amount keys as well as thespecial keys may be employed to perform special functions byhaving.thediiferential mechanism I DIFFERENTIAL MECHANISM nonACCOUNTING-MACHINES.

Specification of Letters ?atent. Patented Sept, 14, 1915,Applicationfiled December 31,1913. Seria1iTo.809,7 09.

controlled thereby perform other functions than controlling the extentofmovement of the amountdifferential mechanism. For ex ample, thedifferential mechanism'for either the amount or the special keys shownmay be designed to control a 'clerks indicator, predetermine a drawer tobe opened in a,

multiple drawer machine such asshown in Letters Patent of. the UnitedStates .No.

set forth in appended claims, and a" preferred form of embodimentofwhich is hereinafter described with reference to the drawings whichaccompany and form part of the specification. I

Of said drawings: Figure 1 is a right handside elevation of the type ofmachine,

shown in theabove mentioned patent granted to Cleal and Reinhart, withthe present invention applied thereto, and showing the differentialmechanism, controlled by the special keys, and omitting the totalizingmechanism. Fig. 2 is a detail view showing the locking detent for thespecial keys. Fig. 3 is a transverse vertical section through themachine taken just to the left of the supporting frame 1, shown in Fig.1, and showing the differential mechanism controlled bv the amount keysin the divided bank and the locking detent for these keys. Fig. 4c is aright hand side elevation of the machine with'the upper part of the sideframe partly broken away and showing locking means for the motor drivenoperating mechanism.

7 The totalizing mechanism is omitted in this keys in the divided bankand shows the gears mounted on the totalizer shaft with this totalizerwheel.

The machine proper is provided with a plurality of banks of amount keys2 and each of the banks of the amount keys of the lower denominationcomprise nine keys, as shown in Fig. 4, and these keys as usual arenumbered from 1 to 9 beginning at'the bottom of the bank. The bank ofkeys, shown in Figs. 1 and 3, includes three amount keys 2, which arethe three upper keys of the bank, and six special keys 3, which are thelower keys in the bank. These three amount keys are described herein asbeing the 1 2 and 3 keys of greatest denomination. This bank of keys isarranged at the left side of the machine, and as this bank comprisesthese two groups of keys it will be called herein the divided bank. Thekeys in this divided bank as Well as the keys in the emaining banks ofkeys are carried in key frames which are concentric with a central shaftl. lVays are cut in each frame to permit the keys to be pressed inradially toward the shaft 4, against the tension of their springs 5.These springs as usual are coiled about the shanks of the keys and serveto normally retain the keys in undepressed position and to restore themto this position at the end of the operation of the machine.

Amount lacy s detent mecham'sm.The amount keys of the divided bank, aswell as the keys of the remaining banks, are provided with means forlocking them in depressed position, and as this means is old in the art,it will be but briefly described here. The locking mechanism for theamount keys of the divided bank is shown in Fig. 3 of the drawings. Thislocking mechanism includes a locking member or detent 7 pivoted onthe'central shaft 1 of the machine, and its free end forms an areconcentric with the arc in which the keys are placed. The curved forwardend of the 'de tent 7 is provided on its one side with laterallyprojecting lugs 8, one of which is provided for each amount key in thebank. When any one of the amount keys is depressed against the tensionofits spring 5, the inner beveled end 9 of the key engages the lug 8 andcauses the detent to rock upward about its pivot. In this position thelug 8 immediately adjacent and below the one which was engaged by thekey will have entered the slot 11 formed in the depressed key, andretain the key in depressed position. \Vhen the locking members 7 is innormal position, the lower forward end 12 rests, as shown in Fig. 3, inengagement with a notch formed in the upper edge of a plate 13, which ismounted to slide upon the central rock shaft 1 of the machine and a pin14 projecting from the frame 1 of the machine and passing through theslot 16 in the plate.

end of the operation of the machine, theplate 13 is given a forwardmovement and the member 7 is lowered by its spring 17 to release theoperated amount key, in the manner well known in the art.

It is customary in machines of the present type to provide meanswhereby, when an amount key is depressed in error, the same may bereleased before an operation of the machine is begun. This meanscomprises a shaft 18 extending longitudinally across the front of themachine, and bearing pins 19 (Fig. 3) each of which is normally out ofengagement with a corresponding pin 20 on the forward end-of the slidingplate 13. The shaft 18, as shown in Fig. 4 has fast to its right handend a small operating lever 21. A spring 22, connecting a pin 23 on thelever 21 and a stationary screw 21, normally holds the lever 21 andshaft 18 in the position shown in the drawings. Vhen it is desired torelease any amount key, which is depressed in error, it is necessarymerely to press down on the forward end of the lever 21, thereby rockingthe shaft 18 to cause the pins 19 carried thereby to engage the pins 20on the plates 13. This movement of the shaft will draw the plate 13 foreach bank forwardly a suflicient extent to withdraw the lockingshoulders 15 from beneath the dentent members 7 thereby permitting thelatter to be lowered to release the depressed amount keys.

Amount clz'fi'erential meclumswa-The differential mechanism for theamount keys in the divided bank is in substance the same as thatprovided for the amount keys in the other banks. This differentialmechanism for the amount keys of'the divided bank is shown in Fig. 3 andbeing well known in the art will be but briefly describedhere. Uponrearward movement of the sliding plate 13. an upward extension 25thereof will bewithdrawn from a pin 26 projecting from a latching bar 27which is suitably mounted upon a toothed segment 28 which, in turn, isloosely mounted upon the central rock shaft 4-. This latter shaft hasfast thereto a downwardly and rearwardly extending arm 29 connected by alink 30 to an arm 31, which is rigidly mounted upon the main drive shaft32. This shaft 32 is given a complete rotation once during eachoperation of the machine, and through the arm 31 link 30, and arm 29rocks the shaft 1 first in a clockwise direction then in the reversedirection slightly past its normal position and then back in a clockwisedirection to normal position.

Secured to the rock shaft 4 are driving plates or segments35, one foreach bank of amountkeys, and eachof these plates is provided with ashoulder 36' with which the latch bar 27 engages when the shoulder isbrought opposite the rear end of the latch V bar upon downward fmovementoftheplate 35, so that when the plate 35 is returned to normal positionit will carry along with it the latch bar 27 and as the latter, ismounted upon segment 28, the plate35 will also carry along with it thesegment 28. Pivotally mountedupon-each segment 28 below the latch bar 27is an arm'37 which carries a spring pressed pawl 38. As the segment 28is rotated rearwardly, thatis counter clockwise (Fig. 3) by the abovedescribed means, the pawl 38 will engage the depressed amountkey androck the arm 37 about its I pivotal point causing the arm in turn torock the latch bar 27 out of engagement with the shoulder 36 of theplate 35, so that the plate may continue its movement independently ofthe segment gear 28.

Thesegment gear 28 controlled by the amount keys2 engages with anintermediate gear 40, which is loosely mounted upon the transverse shaft41 immediately to the right of the frame 1' and the gear 40 in turn-meshes with'the pinion 42 secured to an indicator wheel 43, whichcarries the three amounts represented by the three amount keys of'thisbank, and displays the amount corresponding to the Value of the key de-"pressed; The gearwheel 40, controlled by the amount keys of the dividedbank also meshes with a pinion 150 (Figs. 3 and 6) V which is looselymounted on a totalizer shaft 151. Rigid with the pinion 150 but ofsmaller diameter is a pinion 152 having butv six teeth; A pinion 153which is of the' same diameter as the pinion 152Qand has twenty teeth,is loosely mounted beside the pinion 152. The totalizer wheel 154 isrigidly connected to the pinion 153 by a sleeve 155 surroundingthe'shaft 151. Before the upward return movement ofv the driving plates35 is begun, a coupling pinion 156,

which is sufficiently broad to engage both of the pinions 152 and 153,isthrown into mesh with thejteeth of the pinion 153. The six teeth onthe pinion 152 are so arranged that the pinion fmust have impartedthereto the first six steps of movement of the segment gear'28 from Zeroposition through the medium of the gear 40, before its teeth will engagethe broad pinion. If the 1 key, in the divided bank is depressed thesegment gear "28 will receive seven steps of movem'ent from its zeropositionbefore the pawl 38 engages the depressed key and the seventhstep. of movement, through the gear 40, pinions 150 and 152, broadpinion 150 and pinion153,*will be transmitted to the totalizer wheel 154to add one thereon. In a similar manner the totalizer will receive twoorthree steps of movement if the 2 or 3 keys respectively are depressed.It is to be understood that the differential movement of the segments 28for the amount banks of keys of lower denominations is transmitted tothe corresponding totalizer 7 wheels in a similar manner, only thepinions 152 for these banks of keys have as many teeth as the pinion 153so that the totalizer wheels may be moved fromone to nine stepsdependent upon the keys depressed. Each of the coupling pinions 156 ismounted on a' I corresponding arm 157 which is rocked to engage anddisengage the companion pin ions 152 and 153 at the proper time, in themanner fully described in the above mentioned patent granted to Clealand Reinhart. Special key detent meokam'sm-.The

special keys 3, as shown in Fig. 3, are not.

without effecting in any way the'locking mechanism or differentialmechanism for the amount keys. .PlIlS 45 which project from the lefthand side of the special keys 3 beyond the left hand side of the frame1,

are provided with rollers46 which are not quite as long as the pins 45.

The pins on the amount keys-2 of the divided bank do not project beyondtheleft hand side of the frame 1. The pins 45 on the special keys, attheir free ends and beyond the rollers 46,

pass into the slots 47 out in the forward edge of a plate 48, which isrigidly mounted on the screws 49 projecting from the left side of theframe 1. This movementof the pins 45 in the slots 47 is provided toprevent the pins from being twisted or bent when the keys are depressed.r A locking detent 50 (Figs 2) which is concentric. with the centralrock shaft 4 is provided'at its upper and lower ends with oppositelyextending notches 51, which straddle the screws 49 in such a manner asto permit movement of the detent on the pins. When a special key isdepressed, it

can be seen that the roller 46, carried on its pin 45, will engage theinclined edge 52 of the slot 53 in the path of the roller on the key andwill raise the detent until the roller has passed off ofthe inclinededge 52. Then a-spring 54, connecting anextens'ion-55 on the lower endof the detent with a stud 56 on the frame of the machine will draw thedetent downward so that the setoif 57 in the notch. will pass over theroller and. hold thekey in depressed position. If a key has beendepressed in error, the correct key may beidepressed to raise the detent50 as before and as the setofl 57 is carried: away from the roller 46 onthe first depressed key its spring 5 returns it to initial position andthe correct key is then held in depressed posi-v tion. A roller 58, towhich the spring 5a is fastened, normally engages the beveled edge 59 onthe-upper edge of a sliding plate 60, which is constructed similarly tothe sliding plate 13 for the amount keys and is adapted to be guided inits movements by the central shaft l and the pin let whichalso projectsto the left of the frame 1. Near-its rear end, the plate 60 carries ananti-friction roller 62, which plays in a slot 63 in a driving plate 6fast to the central shaft The upper portion of the slot is concentricwith the central shaft l so that when the shaft is rocked in a clockwisedirection the roller 62 idly plays in this portion of the slot. Near theend of the operation of the machine, however, the shaft, and thereforethe plate 64: is rocked in a reverse direction past the normal positionshown in Fig. 1 and, as the lower portion of the slot is cocentric withthe shaft l, the plate 60 is given a movement toward the front of themachine causing the beveled edge59 of the plate, through its engagementwith the roller 58, to force the detent 5O upward. This upward movementof the detent carries the corresponding setoff 57 in the notch 53 awayfrom the roller 46 on the depressed key, to permit the spring 5 for thekey to return the key to undepressed position. Finally the plate 6 isagain rocked in a clockwise direction to the normal position shown, topermit a spring 66 connecting the plate 60 with a stationary part of themachine, to draw the plate 60 rearwardly again and thereby permit thedetent 50 to be lowered to normal position by its spring 54:.

Difi'ercatz'al mechanism controlled by special 7::eys.-L-oosely mountedupon the left hand end of the central shaft t is a plate 67 having asegmental rack portion 68 engaging with an intermediate gear 69. Thisgear 69 constantlymeshes with a pinion 70 rigid with the specialindicator wheel 71 loosely mounted on the shaft 44 and serving topresent an indication corresponding to the adjustment of the segmentalgear 68 which is accomplished by the following mechanism: A right angledlever 72 is. loosely mounted at 73 to a forwardly extending projection74 of the plate 67. Pivoted to the lever 72 at 75 is a link 76, which atits lower or inner end carries a roller 77 playing in a slot 76 formedin the plate 67. A spring 79 is under tension between a stud 80 on theplate 67 and. a pin 81 projecting from the link 76. The spring 79operatesin a slot 82 formedfinthe plate 67. 726s provided with an arm84: extending inwardly. fromthe pivot 73 and a laterally extendingflange 85 on the arm S'l normally engages. the: edge 86 of: a latch pawl87 loosely; mounted at 73 on the plate 67. A. spningr 83; under tensionbetween the arm 8 and; a hooked projection 89 on the pawl 87;noiunallymaintains this engagement of the flange85'with the edge86. Thelatch pawl 87. is equipped with a notch 90 the projection forming thelower wall of which isllonger than the projection. forming theuppeirv-sallof it lVhena special key is de pressed and the machineoperated the plate Gide-rocked downward an invariable extent with theshaft a, the plate-being rigid with the latter, and. a. notch 91 is theperiphery of; the moving; plate isv carriedj beneath the roller, 77! on.the, link, 76. lVhen the notch 91; is, brought into-this position thespring 79 pullsthe link 76 toward the central shaft 4, untilthe roller77 rests in the notch 91. The projection 92 above the notch, 91 projectsbeyond the periphery of the plate 64 below the notch to prevent thenotch 91 froxnpassingbelow theroller 77 and there by not allowing thespring 79 to pull the link76 inward to engage the notch with. the roller77 which might readily happen on a sudden; operation of the machine. Tofurther-insure=the passage of; the roller 77 into t heinotch 91,whenever the latter is beneath; the former the outwardly extendingportion 9% of the lever 72 is so designed,.that ifthe projection 9.2 onthe plate engages the roller 77 and the spring 79 fails to seat theroller-in the notch, the portion 94 will entheipin 45 on the depressedkey whenever it: reaches the latter in the clockwise movement of, thesegment gear 68 and, rock the lever 72 counter clockwise about itspivotal })OlI1l31'tO force the roller 77 into the notclrQI. If theroller is properly seated in the notch by the spring 79 the projection94: of the lever 72 will merely pass below. thepin 45 on the depressedkey without engaging it. As the plate 67 is not rocked downward farenough. to permit the pin 45 on the bottom key to be engaged by thelever 72 when this key is depressed, a pin 95on the plate 48 is Providedfor this purose. p As shown in Fig. 5, after the link 76 has been drawninwardly, a. notch 96 on the lower forward, end of. the link is carriedout of, engagement, with a pointed projection 97 of; the-latch pawl 87,and the latch pawl is rocked, about itspivotal point, by the lever 72astheflange 85 on the lever engages the edge 8610f thepawl as mentionedabove. As the plate 64- carries the plate 67 down wardthe latclrpawl 87engages. the pin $5 on the depressed key and the pawl is rocked counterclockwise about its pivot tension:

The lever .spring 83 rocks it back into the position shown in Fig. 5. Onthe return stroke of the plates 64 and 67 the lower wallv of the notch90 in the pawl 87 engages the pin on the depressed key and rocks thepawl 87 and therefore the lever 72 about their common pivotal center 73and in this manner draws the link 76 forward, to carrythe rollers 77 onit out of engagement with the notch 91 in the plate 64. Asthe pawl 87 isso rocked about its pivot the pointed projection 97 of the pawl engagesthe notch 96in the link and holdsthe pawl rigid with the link and inthis manner prevents the pawl from moving in either a clockwise orcounter clockwise direction. which might permit it becomlng dlsengagedfrom the toothed portion 68 and the intermediate gear 69 will rotatetheindicator 71 to display a character corresponding to that on the keydepressed. The intermediate gear 69 carries a notched alining plate 100and the notches in the plate are adaptedto be engaged by the bevelednose of an alining pawl 101. The alining pawl 101 is fast to a rockshaft 102 which also carries a downwardly extending arm 103. A'roller104carried-at the lower end of this arm 103 is normally engaged with thecurved periphery of the 7 open cam 105 to hold the alining pawl inalining position with the notched plate 100, while the machine is not inoperation. The open cam 105 is fastto the rotation shaft32 and the camis so arranged on the shaft that, at the beginning of the operation ofthe machine it is carried out of engagement with the roller 104 topermit the adjustment of the indicator wheel 71' and near the end of theoperation of the machine the cam 105 again engages the roller 104 torockthe pawl %01 into alining engagement with the plate 00.

Motor controlling mecham'sm.-It is desirablethat machines of this typebe provided with. electric motor operating mecha-v nism, in order todispense with the hand operated crank, which was formerly employed.

The motor mechanism which it is desired to use in connection with thepresent machine is of a form which is old and well-lmown in 'UnitedStates to C. F. Kettering, No. 910,690 issued January 26,1909, andreference may be had to this patent for a detail description of themotor mechanism. By-referring to this patent, itwill be found that themotor is not positively connected to the main drive shaft of theregister, but that a clutchconnection is interposed between the twowhich clutch connection-in the present invention is controlled by thespecial keys. r

The motor mechanism and the direct control of the special keys over theclutch connections'are shown in the present application, to show thearrangement of this mechanism with relation to the special keys whichnow form, as described'above, a group of keys of the divided bank.Mechanism is also provided whereby a second operation of the machine isprevented when one of the control ling keys is held in at the end of aprevious operation. It has been found that in practice this is oftenattempted by persons, who attempt to misoperate the machine to cover upoperations-in which the proper amounts are not entered in the machine.In these attempts it is customary to push in one of the controlling keysand hold it indepressed positi on at the end of the first operationthereby keeping thev circuit for the motor closed and permitting animmediate second operation of the machine to destroy the indication ofthe first operation. This would prevent the reading of the falseindicationby the customer or other persons in the store. With theconstruction shown in Fig. 1 it is rendered necessary to permit acomplete release of the operated controlling key and its restoration tonormal position before a second operation of the machine may beeffected.

1n the drawings, only a portion of the clutch is shown (Fig. 4). Thisform of clutch has become well-known in the art, and it is not thought.necessary to describe it in detail in the present application. In theform of clutch shown in the Kettering patent above mentioned, a clutchmember 108 is adapted to be given a slight preliminary movement in aclockwise direction as viewed in Fig. 4, about a shaft or stud 109 underthe action'of a coiled spring (not shown),

to render the clutch effective. The clutch member 108, however, isnormally restrained from such movement by the engagement of a at 118 tothe right hand frame of the machine, The lever 112 on itsrearwardlyextending arm, also carries a lug 114, which normally engagesa shoulder: 119 formed on a disk 120 fast on the shaft 41. As will benoted from the train of gearing, comprising the-gear wheels 121, 122 and123, the shaft 4land the main drive shaft 32,,carrying the gear wheel122, are adapted to be given a single rotation at each operation of themachine. Connected to a downwardly extending arm 124 of the lever 112 isa spring 125 which normally tends to rock the lever 112 about its pivot113 to withdraw the lug 114 from engagement with the shoulder 119 of thedisk 121 and also withdraw the flange 111 from the path of the flangecarried by the clutched disk 108 and thereby render the clutcheffective, release the motor, and permit the operation of the machine.The movement of the lever 112 in this manner is prevented, however, byreason of the engagement of a lug 126 carried at the forward end of thelever 112 with the lower face of a projection 127 of an arm 128 fast toa rock shaft 129 which extends longitudinally across the bottom of themachine. Fast on therock shaft 129 and near the left hand sideof themachine. (Fig. 1) is an arm 130, and the rear edge of this arm normallyengages a flange 131 projecting laterallyfrom an: arm 132 forming partof a sliding plate 133. This sliding plate 133 at its upper and, lowerends is provided with notches similar to the notches 51 in the plate 50(Fig. 2) and these notches straddle the pins 49 extending to the left ofthe detent 50 to permit movement of the plate 133. This plate 133 isalso provided with notches 134 there being one notch for each of thespecial keys 3. When one of the special keys is depressed its roller46'engages the inclined upper face of its notch 134 and raises the plate133 to bring the flange 131 on the plate opposite a cut 135 in the upperrear edge of the arm 130. lVhenthe lug 131 is brought in this position,a spring 136 (Fig. 4) connecting the arm 128 to the frame of the machinedraws the arms 128 and130'rearward. The projection 127 on the arm 128 isin this manner carried away from the lug 126 on the lever 112 and thespring immediately acts to rock the lever 112 about itspivot 113 therebyreleasing the operating mechanism as hereinbefore described. Uponoperation of the machine, after the shafts 32 and 41' have been givennearly one rotation, a pin 137 carried by the gear wheel 122 engages therearward end of the lever 112 thereby rocking the lever 112 about itspivot 113 against the tension of its spring 125 back to normal lockingposition. When the sliding plate 60 is moved forwardly near the end ofthe operation of the machine, as de scribed, a, pin 138 engages the armand in this way rocks, the arm 130 forwardly. This, movement of the arm130 rocks the shaft 129 to also carry the arm 128 forwardly andbring'the projectionv 127." into locking engagement with thelug 126,,thereby locking the lever 112 against movement until the next operationof the machine.

As shown in Fig. 1 the arm 130'has pivotally mounted at its upper end anarm 140 arm 130 is rocked inwardly the flange 141 of the arm 140 merelyslides on the upper edge of the flange projection 131. hen the arm 130however, is rocked forwardly near the end of the operation of themachine, as above described, the flange 141 is carried forwardly anextent suflicient to slide out of engagement with the flange projection131 and then falls over the cut in the arm 130. If the key is held indepressedposition at the end of the operation of the machine, the arm130 and the arm 128 can not be rocked slightly forward again to thenormal position shown in the drawings as the vertical rear face of theflange 141 abuts against the projection 131 of the plate 133. hen thekey is released, however, the plate 133 is lowered and, as the flangeprojection 131 passes out of engagement with the vertical face of theflange 141, the spring 125 draws the arms 130 and 128 backward to normalposition. It can be seen in Fig. 4 that the lower face of the projection127 on the arm 128 is sufliciently long to permit the arm 128 to rockforward past its normal position as just described.

From the above description it is obvious that when a special key isretained in depressed position at the end of the operation of themachine, the arms 130 and 128 are prevented from rocking rearward by thepresence of the flange 141 on the arm over the cut 135 in the arm 130,which through the projection 127 on the arm 128 not being carried awayfrom the lug 126 on the lever 112 serves to prevent a second operationof the machine.

A lever 144 (Fig. 4) is loosely pivoted at 24 and at its forward end isprovided with a slot 145 which straddles the pin 23 on the handle 21employed to release the depressed amount keys before the machine isoperated as described. pressed the lever 144 is rocked and a projection146 on the lever passes into. a notch 147 on the arm 128 to preventmovement of the arm and thereby the releasing of the machine by thespecial keys. hile the machine is in operation the projection 148 on thearm 128 is under the projection 144 on the lever 145 so that movement ofthe lever 144 at such time is prevented and hence the handle 21 cannot,during operation of the When the handle 21 is de- 1 be stated, that themachine is provided with.

a divided bank and that one key in each group of keys comprising thebank can be depressed at the same operation of'the machine. Each groupof keys in the bank is provided with locking means and each group ofkeys controls its individual differential mechanism, the differentialmechanism of each group being entirely independent of each other. It canbe further seen that the special keys in the bank control the machinereleasing means as is usual in the art. j 7

While the form of mechanism herein shown and described is admirablyadapted to fulfil the objects primarily stated, it is to be understoodthat it is not intended to confine the invention to the one form ofembodiment herein shown and described, as

ing means for each group of keys whereby.

one key in each group of the bank of keys may be depressed and locked indepressed position at one'operation of the machine; a main drive shaft;andindependent differential mechanism for each group of keys each drivenfrom the main drive shaft, the keys in each group in the bank beingdesigned to predetermine the extent of movement of its correspondingdifferentialmechanism.

'2. In a machine of the class described, the combination with'a maindrive shaft; of an upright frame; a key frame mounted thereon and curvedin form; two groups of keys carried in said key frame; and independentdifferential mechanism for the groups of keys loosely mounted on saidshaft at both sides of said frame and driven from said shaft, the extentof movement of each dif ferential mechanism being predetermined by itscorresponding group of keys at the same operation of the machine.

3. In a machine of the class described, the combination with abank ofkeys, comprising two groups of keys; independent looking means for eachgroup of keys so designed that any key ineach group of the bank of keysmay be depressed and locked in depressed position at one operation; amain drive shaft; independent differential mechanism for each group ofkeys each driven by the main drive shaft but normally disconnectedtherefrom; and latch mechakey is held in such nism for each differentialmechanism for connecting each differential mechanism independent of theother to the main drive shaft, each group of keys being constructed tocontrol its corresponding latch mechanism and thereby determine theextent of movement of its corresponding differential mechanism.

a. In a machine of the class described, the combination with a bank ofkeys, comprising two groups of keys; of independent locking means foreach group of keys whereby one key in each group of the bank of keys maybe depressed and locked in depressed position at one operation of themachine; a main drive shaft; independent differential mechanism for eachbank of keys and driven from the main drive shaft, the

keys in each group in the bank being designed to predetermine the extentof movement 7 of its corresponding differential mechanism; a locking armnormally locking said shaft from movement; a spring normally tending tomove said arm out of locking position a member normally preventingmovement of said arm; and a plate moved by'one group of keys in saidbank but not by the other group toprevent movement of said member andthereby allow said spring to move said locking arm out of lockingposition.

' 5. In a machine of the class described,"the combination with a mainoperating mechanism; of a spring operated locking arm normally lockingsaid mechanism from movement; a spring operated device for normallypreventing movement of sald locking arm and having a notch; a platebearing a projection normally out of operative relation with the notchin said device; keys for moving said plate to bring said projection intooperative. relation with the notch in said device whereupon said deviceis moved to permit movementrof said locking. arm out of lockingposition; means for restoring said arm 'to locking position; an armpivoted on said device'and'having a flange normally passing over saidnotch in said device and ,movable out of such position upon depresarmpasses out of engagement with the pro- 160M011 on said plate and oversaid notch whereby said flange will abut the end of said projection whensaid device is moved in reverse direction to normal position and preventa second movement of th locking arm out of locking position if thedepressed position at the end of the operation.

6. In a machine of the class described, the combination'with a key bankcomprising .two independent groups of keys; of two independentdifferential mechanisms, one for each group of keys; driving means forthe differential mechanisms and latching inechanisms, one for eachdifferential mechanism for latching each differential mechanism with thedriving means and adapted to engage depressed keys in their respectivegroups of the bank of keys whereby the corresponding differentialmechanisms are disconnected from the driving means.

7. In a machine of the class described, the combination with a key bank,comprising two independent groups of keys; of two independentdifferential mechanisms; a rock shaft loosely carrying said differentialmechanisms; two segment plates one for each differential mechanism andrigidly mounted on said shaft; and latching mechanisms one for eachdifferential mechanism for latching each differential mechanism to saidsegment plates, and adapted to engage depressed keys in their respectivegroups of the bank of keys whereby the corresponding differentialmechanisms are disconnected from their segment plates.

8. In a machine of the class described, the combination with a bank ofkeys, comprising two groups of keys; of pins carried by one group ofkeys; a key frame for carrying the bank of keys; two independentdifferential mechanisms, one for each group of keys in the bank; drivingmeans for the differential mechanisms; latching devices one for eachdifferential mechanism for connecting the corresponding differentialmechanisms to the driving means, one of said latching devices beingadapted to engage the inner ends of the depressed keys of one group ofkeys while the other latching device is adapted to engage said pins onthe depressed keys of the other group of keys in, the bank, todisconnect the differential mechanisms from the driving means.

9. I11 a machine of the class described, the combination with adifferentially movable plate; of an oscillatory driving segment for saidplate and having a constant extent of movement and a notch in itsperiphery; a lever pivoted to said differentially movable plate; a linkpivoted at one end to said lever; a roller carried by said link andadapted to engage said notch in the driving segment; a spring connectingsaid link and said differentially movable plate for moving said linkwhen the notch in the plate is opposite the roller; a pawl carried bysaid differentially movable plate; a plurality of keys; and pins on saidkeys adapted, when the keys are depressed, to be engaged by said leverwhen the differentially movable plate is moved in one direction wherebythe link is positively moved to insure engagement of said roller in saidnotch in the driving segment, and adapted to be engaged by said pawlwhen the plate is moved in the opposite direction to move said linkwhereby said roller is carried out of said notch in the driving segment.

10. In a machine of the class described, the combination with a.differentially movable plate; of an oscillatory driving segmenttherefor; an element pivoted on said differentially movable plate; alatch bar having a notch and pivoted to said element and adapted toconnect said differentially movable plate and said driving segment;means for moving said latch bar for this purpose; a pawl carried by saiddifferentially movable plate and provided with a projection and a notch;a plurality of depressible keys; and pins on said keys for engaging saidnotch in said pawl, whereby the pawl is rocked to move said latch barout of connecting position and the projection of the pawl engages thenotch in said link to positively prevent excess movement of saiddifferentially movable plate.

11. In a machine of the class described, the combination with a key bankcomprising two independent groups of keys; of two independentdifferential mechanisms, one for each group of keys; driving means forthe differential mechanisms; and latching mechanisms one for eachdifferential mechanism for latching each differential mechanism with thedriving means and adapted to be controlled by the depressed keys intheir respective groups of the bank of keys whereby the correspondingdifferential mechanisms are disconnected from the driving means.

In testimony whereof I affix my signature in the presence of twowitnesses.

HAAKON A. MARTIN.

Witnesses:

CARL Bnos'r, J. B. Rronn'r'rs.

Copies of this patent may be obtained for five cents each, by addressingthe Commissioner of Patents, Washington, I). G.

